No problem, we've got 6438 and 2100 to multiply
6438 × 2100 = 2100 × (6438)
+ 2100 × 8 giving us 16800
+ 2100 × 30 that is equal 63000
+ 2100 × 400 that results in 840000
+ 2100 × 6000 that equals 12600000

= 13519800
